Prior Lake Water Hardness & Quality Report (2026)

Prior Lake, Minnesota, in Scott County southwest of the Twin Cities, receives its municipal water from the City of Prior Lake Water Utility, which operates a combination of municipal wells drawing from the Prairie du Chien-Jordan Aquifer and surface water supply through the metropolitan regional grid. The Prairie du Chien-Jordan is a major confined aquifer underlying southern Minnesota — a sandstone and dolomite sequence of Ordovician age that supplies numerous communities across the region. Prior Lake also draws on connections to the Metropolitan Council regional water supply infrastructure for supplementary supply.

The hard 165.5 mg/L hardness is a product of the Prairie du Chien Formation — an Ordovician-age dolomite that dissolves readily into confined groundwater during long subsurface residence times. The formation's calcium magnesium carbonate mineralogy releases high concentrations of bicarbonate hardness, which is characteristic of communities in Scott, Carver, and Dakota counties drawing from this aquifer system. Surface drainage across Scott County's glacial till plains — composed of ground-up Paleozoic limestone and dolomite from Pleistocene ice advances — adds further dissolved calcium to the supply blend.

At 165.5 mg/L, Prior Lake has hard water, and mineral buildup affects household appliances with regularity. White scale forms visibly in kettles within weeks of use, dishwashers leave mineral deposits on glassware, and showerheads benefit from periodic vinegar soaking to restore full flow. Water heater efficiency declines over time without maintenance. Descaling every two to three months keeps heating appliances operating efficiently. Many Prior Lake homeowners invest in a whole-house water softener to protect their plumbing and appliances — particularly relevant given the hard water is uniformly distributed across all fixtures.